Tweak apply and short-fn docstrings

[sogaiu]

This PR suggests tweaking the docstrings for apply and short-fn.

The changes are mostly about removing the contained examples, though there is also a slight clarification about the & args portion of apply as well.

During the 2025 Janetuary Community Project, a number of us studied and added some examples to the janet-lang.org repository.

We scanned through the existing docstrings and found that there were only four [1] that contained examples. apply already had examples at janet-lang.org and we added comparable ones for short-fn. It seems redundant and inconsistent [2] to keep the examples in the docstrings so this PR is a proposal to remove them.

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On a side note, the remaining two items we found examples for in docstrings were:

• debug/break
• fiber/new

Assuming this PR (or something similar) is accepted, once appropriate examples have been added to janet-lang.org for the remaining two, we're thinking to do similarly for them too.

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[1] It's possible we missed some, but it seems unlikely there are too many more.

[2] The inconsistency also manifests visually at the Core API page (and may be some would think it doesn't look that nice):

[bakpakin]

Thanks, the new docstring definitely reads better.